I need to see Dave’s sister

I don’t care for Dave or this sister that apparently has so much control over him, but at this point I need to see who she is and why she holds so much over him. At one point I was thinking she doesn’t exist and it’s just a person he’s using to make up excuses for his treatment towards Lauren. I feel bad that Lauren has to deal with this but I can tell she really wants to be married. I just want her to realize there’s MUCH more out there than a guy that makes you cry everyday!